Method of manufacturing diamond studded tools



Dec. 28, 1948. p JONES METHOD OF MANUFACTURING DIAMOND STUDDED TOOLS FiledJan. 12, 1946 Patented Dec. 28, 1948 UNITED STATES PATENT OFFICEMETHOD OF MANUFACTURING DIAMOND STUDDED TOOLS John Paul Jones, Toronto,Ontario, Canada Application January 12, 1946, Serial No. 640,939 3Claims. (Cl. 51-309) This invention relates particularly to the methodby means of which the small diamond particles are embedded in the metaltool body and the principal object of the invention is to effectivelyhold the diamond particles within the small placement cavities in thesurface of a ceramic mould while the metal of which the tool body isformed is being cast in said mould to imbed the diamond particles fromsubsequent displacement in the operative use of the tool.

A further object is to accomplish the desired result in a simple andinexpensive manner.

The principal feature of the invention consists in the novel method ofsecuring diamond particles partly' embedded within placing cavities inthe surface of a mould by efiecting adhesion of the particles to themould through the fusion of a medium which will adhere to the mouldsurface and the surface of the diamond and will withstand the eiiort ofa body of molten metal poured into the mould to displace the diamondparticles from their placing cavities in the mould and hold suchparticles embedded in the metal poured into the mould until such moltenmetal will have securely and permanently embraced a portion of each ofthe diamond particles.

In the manufacture of diamond studded tools it has been the practice toform moulds, for the casting of molten metal to form a tool head, of aceramic material and the particles of diamond have been partly embeddedin the ceramic.

Owing to the fact that it is undesirable to subject the diamond to thetemperature required for firing the ceramic to efiectively mould amolten metal, such moulds have been formed with placing cavities and thediamond particles have been secured in these cavities by adhesives ofvarious kinds but it has been found that the heat of the molten metalpoured into the mould destroys or renders these adhesives ineflectiveand the wash or flow of the molten metal displaces the diamond particleswith the result that an undesirable percentage of the diamonds are lostin the cast metal, that is, they are not held on the surface in aneffective cutting position.

The method herein set forth is illustrated in the accompanying drawingsin which Figure 1 is an underside perspective view of a diamond drillfor coring.

Figure 2 is a perspective view of the mould for forming the diamondstudded end of the core drill.

view through the mould.

Figure 4 is a magnified sectional view of a portion of a mould showing adiamond coated and Figure 3 is an enlarged vertical mid-sectional readyto be embedded in an adhesive-coated positioning cavity.

Figure 5 shows the coated diamond inserted into an adhesive coatedpositioning cavity.

Figure 6 is a magnified sectional view of a portion of a mould showing adiamond secured in I its positioning cavities with the melted adhesive.

Figure 7 is a view similar to Figure 6 showing the metal of the toolhead moulded around the portion of the diamond projecting beyond themould cavity.

In carrying this invention into effect a mould of the desired shape andsize is fashioned from a plastic ceramic which will withstand firing ata temperature higher than the melting tempera ture of the metal to bemoulded therein to form the desired tool.

Such a mould l is illustrated in Figure 2 with an annular recess 2formed therein when an annular type of bit is to be made. The innerwalls of this recess 2 are provided with a multiplicity of small placingcavities 3 which may be formed by pressing or cutting the plasticceramic material. The mould thus formed is then fired at a temperaturepreferably several hundred degrees above the temperature of the moltenmetal to be poured therein, say approximately 2150 F.

When the mould has cooled the surface of the cavities 3 is preferablybrushed or otherwise coated with a thin coating l of a suitable adhesive to provide a tacky surface.

The diamond particles ii which are to be used in the tool are thenpreferably dipped to coat a portion of the surface with a suitable tackyadhesive e and while the adhesive is tacky the diamond is dipped in afine frit or powdered glass, thus applying a coating ll of such frit toa portion of the surface of the diamond. &

The frit covered portion of the diamond is then pressed into theadhesive coated placing cavity 3 and it is thus temporarily securedtherein,

When all the placing cavities have been thus filled the mould is placedin a furnace and its temperature raised to a point which will dis sipatethe temporary adhesive and fuse the int and bring it to a tacky state sothat it will adhere strongly to the diamond surface and to the mouldsurface. Such temperature will be approximately 1550 F. which issufliciently low to prevent reaction with the diamonds.

The heated mould is withdrawn from the furnace and the molten metal,which is to form the tool head, is poured into the mould at atemperature of approximately 1750 F.

The immediate application of this temperature from the molten metal tothe mould, which is already heated to approximately 1550 F., efiects Ithe positioning cavities.

a further fusion of the glass and it acts as a tenacious temperaturecontrolled adhesive to prevent the wash of the metal pouredv into themould from displacing the diamond particles from The molten metal flowsaround the portions 8 of the diamonds protruding from the cavities 3 ofthe mould and it may partly enter the cavities but will not displace thefused frit adhesive from around the portion of the diamond embedded inthe cavities.

Immediately the metal begins to cool it shrinks around the diamondparticles which it has surrounded and thus permanently embeds suchparticles in the metal casting.

, In the process described each particle will be a high melting pointand capable of assuming a firmly held in its proper position in themould by the fused frit and be instantaneously embedded and sealed inthe cast metal tool.

It will be readily understood that a process such as described may beput into effect without the use of special expensive tools andequipment.

The diamond particles have to be handled and placed in positioningcavities in any of the known methods and in the present method it ismerely necessary for the operator to dip the diamond first in theadhesive then in the frit and then insert it in the positioning cavitywhich will have been adhesively coated separately.

Nothing further is required to hold the particles in the cavities. Theoriginal adhesive merely holds until the frit is fused to form theactive adhesive and the taclw glass effectively resists the "was of themolten metal and as the metal cools insertingthe portions of the diamondparticles it simultaneously forms the tool head and seals the cuttingdiamonds therein in proper operating location.

After the tool head is cast in the manner described the mould is simplybroken away from the cast metal and it is then machined and fitted tothe operative drilling tube, rod or other implement.

In the manufacture of certain classes of tools it may be found desirableto dispense with the use of the temporary adhesive by dusting orotherwise placing frit or powdered glass in the cavities and applying atemperature to the mould sufilcient to fuse the glass particles andinsert the diamond particles into the cavities to be adhered to thefused material.

It may also be found feasible to use powdered metal as a fusible binderto hold the diamond particles in the mould.

In the use of any of the powdered fusible adhesives it may be foundpractical to spray or otherwise coat the mould surfaces with a temporaryadhesive, then dust or otherwise apply the frit or other fusibleadhesive to the adhesive surface and then the diamond particles may beinserted into the coated mould cavities.

What I claim as my invention is:

1. A method of manufacturing diamond studded tools consisting inpreparing a mould with diamond placing cavities in its surface,positioning diamond particles in the cavities in said mould, packingpowdered glass in said cavities around said diamonds, said diamondparticles being arranged in the desired orientation in said I cavitiesto provide the correct cutting angles desired in the completed tool andbeing temporarily held in position by said powdered glass packing,raising the temperature of said mould to bring said glass to a tackystate to bond said diamonds in oriented position in said cavities, thenmoulding metal to form the tool around the exposed portion of thediamond particles to form a direct bond between the tool metal and thediamonds, then finally breaking away the mould and the glass.

2. A method of manufacturing diamond studded toolsconsisting inpreparing a mould of a ceramic material and forming placing cavities inits surfaces, firing the mould, embedding diamond particles within saidcavities and surround- .ing the embedded portions with a material havingtacky condition in the transition from the solid to the liquid state,and leaving the unembedded portion of the diamonds free of saidmaterial, applying heat to the mould to raise said high melting pointmaterial to its tacky condition to adhere to the mould and to thediamonds, to hold same firmly embedded in oriented positions in saidcavities, then moulding the tool forming metal around the unembeddedportionsof the 'diamonds' to provide a direct bond between the diamondsand the tool metal, and finally breakin'g away the ceramic mould and thehigh melting point material.

. 3. A method of manufacturing diamond studded tools consisting inpreparing a mould of a "ceramic material and forming placing cavities inits surfaces, applying a temporary tacky adhesive to the surface of thecavities, applying a temporary tacky adhesive to the diamond partitowhich said high melting point material has been applied into saidcavities to contact the tacky adhesive therein, applying heat todissipate the temporary adhesive. and raise said high melting pointmaterial to its tacky condition to adhere to the diamond particles andthe mould, to hold same firmly embedded in oriented position in saidmould cavities, moulding the tool forming metal in the mould to surroundand embrace the portions of the diamond particles protruding from thecavities to provide a direct bond between the diamonds and the toolmetal, and finally breaking away the ceramic mould.

7 JOHN PAUL JONES.

REFERENCES CITED The following references are UNITED STATES PATENTSNumber Name Date 2,147,175 Rolland Feb. 14, 1939 2,147,843 Jamar et alFeb.' 21, 1939 2,187,384 Maier Jan. 16, 1940 2,299,207 Bevillard Oct.20, 1942 2,319,331 Kurtz May 18, 1943 2,363,272 Taeyaerts et a1 Nov, 21,1944 2,368,473 Keeleric Jan. 30, 1945 2,410,512 Lindquist et al. Nov. 5,1946 FOREIGN PATENTS Number Country Date 526,241 Great Britain Sept. 13,1940 556,007 Great Britain Sept. 16, 1943 JTHER REFERENCES

